Optical interface cards, assemblies, and related methods, suited for installation and use in antenna system equipment

ABSTRACT

Optical interface cards, assemblies, and related methods, which may be suited for installation and use in antenna system equipment, are disclosed. In certain embodiments, an optical interface card (OIC) comprising a printed circuit board (PCB) having at least one optical sub-assembly (OSA) mounted to at least one first opening end of the PCB and extending into at least one opening and related methods are disclosed. In other embodiments, optical interface assemblies comprised of two OICs mounted together are disclosed. In other embodiments, a communications equipment enclosure including at least one fan configured to draw in air from a first side of the communications equipment enclosure into a lower plenum and across a plurality of communications components into an upper plenum to provide air cooling are disclosed. In another embodiment, a modular distributed antenna system assembly is disclosed.

RELATED APPLICATIONS

This application is related to U.S. Provisional Patent Application Ser.No. 61/301,495 filed Feb. 4, 2010 entitled “Modular Distributed AntennaSystem Equipment Housings, Assemblies, And Related Alignment Feature,”which is incorporated herein by reference in its entirety.

This application is also related to U.S. Provisional Patent ApplicationSer. No. 61/301,488 filed Feb. 4, 2010 entitled “Modular DistributedAntenna System Equipment Housings, Assemblies, And Related AlignmentFeature,” which is incorporated herein by reference in its entirety.

This application is also related to U.S. Provisional Patent ApplicationSer. No. 61/316,584 filed Mar. 23, 2010 entitled “Modular DistributedAntenna System Equipment Housings, Assemblies, And Related AlignmentFeature,” which is incorporated herein by reference in its entirety.

This application is also related to U.S. patent application Ser. No.12/751,884 filed Aug. 4, 2011 entitled “Communications EquipmentHousings, Assemblies, and Related Alignment Features and Methods,” whichis incorporated herein by reference in its entirety.

BACKGROUND

1. Field of the Disclosure

The technology of the disclosure relates generally to enclosures forhousing distributed antenna system equipment provided in a distributedantenna system. The distributed antenna system equipment can includeoptical fiber-based distributed antenna equipment for distributing radiofrequency (RF) signals over optical fiber to remote antenna units.

2. Technical Background

Wireless communication is rapidly growing, with ever-increasing demandsfor high-speed mobile data communication. As an example, so-called“wireless fidelity” or “WiFi” systems and wireless local area networks(WLANs) are being deployed in many different types of areas (e.g.,coffee shops, airports, libraries, etc.). Wireless communication systemscommunicate with wireless devices called “clients,” which must residewithin the wireless range or “cell coverage area” in order tocommunicate with an access point device.

One approach to deploying a wireless communication system involves theuse of “picocells.” Picocells are radio frequency (RF) coverage areas.Picocells can have a radius in the range from a few meters up to twentymeters as an example. Combining a number of access point devices createsan array of picocells that cover an area called a “picocellular coveragearea.” Because the picocell covers a small area, there are typicallyonly a few users (clients) per picocell. This allows for minimizing theamount of RF bandwidth shared among the wireless system users. In thisregard, head-end communication equipment can be provided to receiveincoming RF signals from a wired or wireless network. The head-endcommunication equipment distributes the RF signals on a communicationdownlink to remote antenna units distributed throughout a building orfacility. Client devices within range of the picocells can receive theRF signals and can communicate RF signals back to an antenna in theremote antenna unit, which are communicated back on a communicationuplink to the head-end communication equipment and onto the network. Thehead-end communication equipment may be configured to convert RF signalsinto optical fiber signals to be communicated over optical fiber to theremote antenna units.

It may be desirable to provide a housing or enclosure for communicationequipment for a distributed antenna system that is easily assembled.Thus, the housing or enclosure can be easily assembled in the field.Further, it may be desirable to provide communication equipment for adistributed antenna system that is compatible with expansion ofpicocells. Thus, it may be desirable to provide communication equipmentfor a distributed antenna system that can be easily upgraded or enhancedto support an increased number or type of remote antenna units, as anexample. It may be further desired to allow technicians or other usersto provide this increased support in the field, thus making it desirableto allow equipment changes and upgrades to easily be made in thecommunication equipment with ease and proper function.

SUMMARY OF THE DETAILED DESCRIPTION

Optical interface cards, assemblies, and related methods, which may besuited for installation and use in antenna system equipment, aredisclosed. In one embodiment, optical interface cards are disclosed.Optical interface cards can provide an interface between optical andelectrical signals in a communication system, including a distributedantenna communication system, as an example. In certain embodiments, theoptical interface card comprises a printed circuit board (PCB) having afirst end and a second end opposite the first end. At least one openingis disposed in the PCB between the first end and the second end of thePCB and having at least one first opening end and at least one secondopening end opposite the at least one first opening end. At least oneoptical sub-assembly (OSA) is mounted to the at least one first openingend and extends into the at least one opening. In this manner, the OSAcan be mounted on an end of a PCB to limit the length of exposed,unshielded wire extensions and printed traces on the PCB. This canprovide for signal integrity of the signals after conversion toelectrical signals.

In another embodiment, an optical interface assembly is provided. Theoptical interface assembly includes a first optical interface card (OIC)that comprises at least one first opening between a first end and asecond end of the first OIC having at least one first opening end, andat least one first optical sub-assembly (OSA) mounted to the at leastone first opening end and extending into the at least one first opening.A second OIC is provided that comprises at least one second openingbetween a first end and a second end of the second OIC having at leastone second opening end, and at least one second OSA mounted to the atleast one second opening end and extending into the at least one secondopening. The optical interface assembly also includes at least onestandoff disposed between the first OIC and second OIC.

In another embodiment, a method of assembling an optical interface cardis provided. The method comprises providing a printed circuit board(PCB) having a first end and a second end opposite the first end. Themethod also comprises mounting at least one optical sub-assembly (OSA)to at least one first opening end of at least one opening disposed inthe PCB between the first end and the second end of the PCB.

In another embodiment, a communications equipment enclosure is provided.The communications equipment enclosure comprises at least onecompartment configured to house a plurality of communications componentsbetween a lower plenum and an upper plenum. The communications equipmentenclosure also comprises at least one fan configured to draw in air froma first side of the communications equipment enclosure into the lowerplenum and across the plurality of communications components into theupper plenum. The communications equipment enclosure also comprises anair outlet disposed on a second side of the communications equipmentenclosure and coupled to the upper plenum to direct air drawn by the atleast one fan into the upper plenum through the air outlet.

In another embodiment, a method of providing air cooling ofcommunications components installed in a communications equipmentenclosure is provided. The method includes drawing in air from a firstside of the communications equipment enclosure into a lower plenum usingat least one fan installed in the communications equipment enclosure.The method also includes drawing the air from the lower plenum across aplurality of communications components installed in the communicationsequipment enclosure between the lower plenum and an upper plenum. Themethod also includes drawing the air outside of the communicationsequipment enclosure through an air outlet disposed on a second side ofthe communications equipment enclosure and coupled to the upper plenum.

In another embodiment, a modular distributed antenna system assembly isprovided. The assembly includes at least one first plate including atleast one first locating alignment slot. The assembly also includes atleast one second plate including at least one locating tab. The at leastone locating tab engages with the at least one first locating alignmentslot to align the at least one first plate in at least two dimensions tothe at least one second plate to form an enclosure configured to supportat least one distributed antenna system component.

Additional features and advantages will be set forth in the detaileddescription which follows, and in part will be readily apparent to thoseskilled in the art from that description or recognized by practicing theembodiments as described herein, including the detailed description thatfollows, the claims, as well as the appended drawings.

It is to be understood that both the foregoing general description andthe following detailed description present embodiments, and are intendedto provide an overview or framework for understanding the nature andcharacter of the disclosure. The accompanying drawings are included toprovide a further understanding, and are incorporated into andconstitute a part of this specification. The drawings illustrate variousembodiments, and together with the description serve to explain theprinciples and operation of the concepts disclosed.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a partially schematic cut-away diagram of an exemplarybuilding and building infrastructure in which a distributed antennasystem is employed;

FIG. 2 is an exemplary schematic diagram of an exemplary head-endcommunications unit (“HEU”) deployed in the distributed antenna systemin FIG. 1;

FIG. 3 is an exemplary distributed antenna system equipment housingassembly (“assembly”) and enclosure configured to support the HEU ofFIG. 2;

FIG. 4 is an exemplary optical interface module (OIM) comprised of apair of optical interface cards (OIC) configured to be installed in thedistributed antenna system equipment housing assembly of FIG. 3 as partof the HEU;

FIG. 5 is a front view of the enclosure of FIG. 3 with a midplaneinterface card of the HEU of FIG. 2 installed therein;

FIG. 6 is a rear side perspective view of the enclosure of FIG. 3 withthe midplane interface card of FIG. 5 installed on a midplane supportinstalled therein;

FIG. 7 is a close-up front, right side perspective view of the midplaneinterface card of FIG. 5 installed on a midplane support installed inthe enclosure of FIG. 3;

FIG. 8 illustrates a front side of the midplane interface card of FIG. 5without connectors attached to the midplane interface card;

FIG. 9 illustrates a rear view of the enclosure of FIG. 3 with adownlink base transceiver interface (BTS) card (BIC) being inserted intothe enclosure and an uplink BIC fully inserted into the enclosure andconnected to the midplane interface card disposed in the enclosure;

FIGS. 10A and 10B illustrate front and rear perspective views,respectively, of BIC assemblies that can be inserted in the enclosure ofFIG. 3 with the BIC disposed in the assemblies connected to the midplaneinterface card disposed in the enclosure of FIG. 3;

FIG. 11 illustrates a bottom view of the BIC assembly of FIGS. 10A and10B;

FIG. 12 illustrates a top view of the BIC assembly of FIGS. 10 and 10Binstalled in the enclosure of FIG. 3;

FIG. 13 is a side perspective view of the assembly of FIG. 3 withdownlink BIC connectors for the downlink BIC and uplink BIC connectorsfor the uplink BIC disposed in downlink and uplink BIC connector plates,respectively, which are attached to the front of the enclosure;

FIG. 14 is a front perspective view of the BIC connector plateillustrated in FIG. 13 with BIC connectors disposed therethrough;

FIG. 15 is a rear perspective view of the BIC connector plate with BICconnectors disposed therethrough illustrated in FIG. 14;

FIG. 16 is a rear side perspective view of the enclosure of FIG. 13illustrating cables connected to the BIC connectors disposed through theBIC connector plates routed through openings in the midplane support tothe downlink BIC and uplink BIC disposed in the enclosure;

FIG. 17 is a top view of the enclosure of FIG. 13 illustrating cablesconnected to the BIC connectors disposed through the BIC connectorplates routed through openings in the midplane support to the downlinkBIC and uplink BIC disposed in the enclosure;

FIG. 18 is a front exploded perspective view of plates of the enclosureof FIG. 3 that are assembled together in a modular fashion to form theenclosure;

FIGS. 19A and 19B illustrate top and bottom perspective views of theenclosure of FIG. 3;

FIG. 20 illustrates a close-up view of the engagement of the top plateof the enclosure in FIG. 3 with a side plate and midplane support of theenclosure of FIG. 3;

FIG. 21 illustrates a close-up view of locating tabs disposed in the topplate of the enclosure of FIG. 3 engaged with alignment slots disposedin the side plate of the enclosure of FIG. 3;

FIG. 22 is a side view of the OIM that can be disposed in the enclosureof FIG. 3;

FIG. 23 is another perspective side view of the OIM that can be disposedin the enclosure of FIG. 3;

FIG. 24 is a rear perspective view of the OIM that can be disposed inthe enclosure of FIG. 3;

FIG. 25 is a perspective view of an alignment block that secures the OICto an OIM plate of the OIM of FIGS. 23 and 24;

FIG. 26A is a rear perspective view the OIM of FIGS. 23 and 24 withoutshields installed;

FIG. 26B is a rear perspective view the OIM of FIGS. 23 and 24 withshield plates installed;

FIG. 27 is a close-up rear view of the OIM of FIGS. 23 and 24 showingstandoffs disposed between two printed circuit boards (PCBs) of theOICs, wherein one of the PCBs is a floating PCB;

FIG. 28 is a cross-sectional side view of the PCBs of the OICs securedto each other via the standoffs of FIG. 27 to provide one of the OICPCBs as a floating PCB and the other of the OIC PCBs as a fixed PCB;

FIGS. 29A and 29B are perspective views of the floating standoffs inFIG. 27;

FIGS. 29C and 29D are side and top views, respectively, of the standoffsof FIG. 31;

FIG. 30 is a side cross-sectional view of the standoff of FIG. 27;

FIG. 31 is a side cross-sectional view of an alternative standoff thatcan be employed to secure the OIC PCBs and provide one of the OIC PCBsas a floating PCB;

FIGS. 32A and 32B are side cross-sectional views of an alternativestandoff that can be employed to secure the OIC PCBs and shield platesand provide one of the OIC PCBs as a floating PCB;

FIG. 33 is a side view of the assembly of FIG. 3 showing an OIC digitalconnector being connected to a complementary connector disposed in themidplane interface card to align the OIC RF connector to be connected tothe complementary RF connector disposed in the midplane interface card;

FIG. 34 is a top perspective view of an OIC disposed in the OIM of FIGS.26A and 26B illustrating the extension of the OIC PCB of beyondtransmitter optical sub-assemblies (TOSAs) and receiver opticalsub-assemblies (ROSAs) disposed in the OIC PCB;

FIG. 35 is a front perspective view of the assembly and enclosure ofFIG. 3 with a cooling fan protector plate installed to protect a coolingfan installed in the enclosure;

FIG. 36 is a side cross-sectional view of the enclosure of FIG. 35illustrating a cooling fan duct disposed behind the cooling fan in theenclosure to direct air drawn into the enclosure by the cooling fan intoa lower plenum of the enclosure;

FIG. 37 is an exemplary schematic diagram of air flow drawn into theenclosure by the cooling fan through the enclosure of FIG. 35;

FIG. 38 is another side cross-sectional view of the enclosure of FIG. 35illustrating the directing of air through openings in a lower plenumplate through OICs installed in the enclosure and through openingsdisposed in an upper plenum plate in the enclosure;

FIG. 39 is a rear perspective view of the enclosure of FIG. 35illustrating an air outlet from the upper plenum of the enclosure;

FIG. 40 is a rear perspective view of the enclosure of FIG. 35illustrating the air outlet from the upper plenum of the enclosure withthe top plate of the enclosure removed and illustrating openings in theupper plenum plate into the uplink BIC compartment of the enclosure; and

FIG. 41 is a top view of the uplink BIC with openings disposed thereinto allow air to flow from the downlink BIC to the uplink BIC disposedabove the downlink BIC in the enclosure of FIG. 35.

DETAILED DESCRIPTION

Reference will now be made in detail to the embodiments, examples ofwhich are illustrated in the accompanying drawings, in which some, butnot all embodiments are shown. Indeed, the concepts may be embodied inmany different forms and should not be construed as limiting herein;rather, these embodiments are provided so that this disclosure willsatisfy applicable legal requirements. Whenever possible, like referencenumbers will be used to refer to like components or parts.

Optical interface cards, assemblies, and related methods, which may besuited for installation and use in antenna system equipment, aredisclosed. In one embodiment, optical interface cards are disclosed.Before discussing the exemplary distributed antenna system equipment,assemblies and enclosures and their alignment features, which start atFIG. 3, an exemplary distributed antenna system is first described withregard to FIGS. 1 and 2. In this regard, FIG. 1 is a schematic diagramof a partially schematic cut-away diagram of a building 10 thatgenerally represents any type of building in which a distributed antennasystem 12 might be deployed. The distributed antenna system 12incorporates a head-end communications unit or head-end unit (HEU) 14 toprovide various types of communication services to coverage areas withinan infrastructure 16 of the building 10. The HEU 14 is simply anenclosure that includes at least one communication component for thedistributed antenna system 12. For example, as discussed in more detailbelow, the distributed antenna system 12 in this embodiment is anoptical fiber-based wireless communication system that is configured toreceive wireless radio frequency (RF) signals and provide the RF signalsas Radio-over-Fiber (RoF) signals to be communicated over optical fiber18 to remote antenna units (RAUs) 20 distributed throughout the building10. The distributed antenna system 12 in this embodiment can be, forexample, an indoor distributed antenna system (IDAS) to provide wirelessservice inside the building infrastructure 10. These wireless servicescan include cellular service, wireless services such as radio frequencyidentification (RFID) tracking, wireless fidelity (WiFi), local areanetwork (LAN), and combinations thereof, as examples.

The terms “fiber optic cables” and/or “optical fibers” include all typesof single mode and multi-mode light waveguides, including one or moreoptical fibers that may be upcoated, colored, buffered, ribbonizedand/or have other organizing or protective structure in a cable such asone or more tubes, strength members, jackets or the like. Likewise,other types of suitable optical fibers include bend-insensitive opticalfibers, or any other expedient of a medium for transmitting lightsignals. An example of a bend-insensitive optical fiber is ClearCurve®Multimode fiber commercially available from Corning Incorporated.

With continuing reference to FIG. 1, the infrastructure 16 includes afirst (ground) floor 22, a second floor 24, and a third floor 26. Thefloors 22, 24, 26 are serviced by the HEU 14 through a main distributionframe 28 to provide a coverage area 30 in the infrastructure 16. Onlythe ceilings of the floors 22, 24, 26 are shown in FIG. 1 for simplicityof illustration. In this example embodiment, a main cable 32 has anumber of different sections that facilitate the placement of a largenumber of RAUs 20 in the infrastructure 16. Each RAU 20 in turn servicesits own coverage area in the coverage area 30. The main cable 32 caninclude, for example, a riser section 34 that carries all of the uplinkand downlink optical fiber cables to and from the HEU 14. The main cable32 can include one or more multi-cable (MC) connectors adapted toconnect select downlink and uplink optical fiber cables, along with anelectrical power line, to a number of optical fiber cables 36.

In this example embodiment, an interconnect unit 38 is provided for eachfloor 22, 24, and 26. The interconnect units 38 include an individualpassive fiber interconnection of optical fiber cable ports. The opticalfiber cables 36 include matching connectors. In this example embodiment,the riser section 34 includes a total of thirty-six (36) downlink andthirty-six (36) uplink optical fibers, while each of the six (6) opticalfiber cables 36 carries six (6) downlink and six (6) uplink opticalfibers to service six (6) RAUs 20. The number of optical fiber cables 36can be varied to accommodate different applications, including theaddition of second, third, etc. HEUs 14.

According to one aspect, each interconnect unit 38 can provide a lowvoltage DC current to the electrical conductors in the optical fibercables 36 for powering the RAUs 20. For example, the interconnect units38 can include an AC/DC transformer to transform 110V AC power that isreadily available in the infrastructure 16. In one embodiment, thetransformers supply a relatively low voltage DC current of 48V or lessto the optical fiber cables 36. An uninterrupted power supply could belocated at the interconnect units 38 and at the HEU 14 to provideoperational durability to the distributed antenna system 12. The opticalfibers utilized in the optical fiber cables 36 can be selected basedupon the type of service required for the system, and single mode and/ormulti-mode fibers may be used.

The main cable 32 enables multiple optical fiber cables 36 to bedistributed throughout the infrastructure 16 (e.g., fixed to theceilings or other support surfaces of each floor 22, 24 and 26) toprovide the coverage area 30 for the first, second and third floors 22,24 and 26. In this example embodiment, the HEU 14 is located within theinfrastructure 16 (e.g., in a closet or control room), while in anotherexample embodiment, the HEU 14 may be located outside of the building ata remote location. A base transceiver station (BTS) 40, which may beprovided by a second party such as cellular service provider, isconnected to the HEU 14, and can be co-located or located remotely fromthe HEU 14. A BTS is any station or source that provides an input signalto the HEU 14 and can receive a return signal from the HEU 14. In atypical cellular system, for example, a plurality of BTSs are deployedat a plurality of remote locations to provide wireless telephonecoverage. Each BTS serves a corresponding cell and when a mobile stationenters the cell, the BTS communicates with the mobile station. Each BTScan include at least one radio transceiver for enabling communicationwith one or more subscriber units operating within the associated cell.

The HEUs 14 are host neutral systems in this embodiment which canprovide services for one or more BTSs 40 with the same infrastructurethat is not tied to any particular service provider. The HEU 14 isconnected to six (6) optical fiber cables 36 in this embodiment.

FIG. 2 is a schematic diagram of the exemplary HEU 14 provided in thedistributed antenna system 12 of FIG. 1 to provide further detail. Asillustrated therein, the HEU 14 includes a number of exemplarydistributed antenna system components. A distributed antenna systemcomponent can be any component that supports communication for thedistributed antenna system, such as the distributed antenna system 12 ofFIG. 1. For example, a head-end controller (HEC) 42 is included thatmanages the functions of the HEU 14 components and communicates withexternal devices via interfaces, such as a RS-232 port 44, a UniversalSerial Bus (USB) port 46, and an Ethernet port 48, as examples. The HEU14 can be connected to a plurality of BTSs, transceivers, etc. at BICconnectors 50, 52. BIC connectors 50 are downlink connectors and BICconnectors 52 are uplink connectors. Each downlink BIC connector 50 isconnected to a downlink BTS interface card (BIC) 54 located in the HEU14, and each uplink BIC connector 52 is connected to an uplink BIC 56also located in the HEU 14. The downlink BIC 54 is configured to receiveincoming or downlink RF signals from the BTS inputs, as illustrated inFIG. 2, to be communicated to the RAUs 20. The uplink BIC 56 isconfigured to provide outgoing or uplink RF signals from the RAUs 20 tothe BTSs as a return communication path.

The downlink BIC 54 is connected to a midplane interface card 58. Theuplink BIC 56 is also connected to the midplane interface card 58. Thedownlink BIC 54 and uplink BIC 56 can be provided in printed circuitboards (PCBs) that include connectors that can plug directly into themidplane interface card 58. The midplane interface card 58 is also indirect electrical communication with a plurality of optical interfacecards (OICs) 60, which are in optical and electrical communication withthe RAUs 20 via the optical fiber cables 36. The OICs 60 convertelectrical RF signals from the downlink BIC 54 to optical signals, whichare then communicated over the optical fiber cable 36 to the RAUs 20.The OICs 60 in this embodiment support up to three (3) RAUs 20 each.

The OICs 60 can also be provided in a PCB that includes a connector thatcan plug directly into the midplane interface card 58 to couple thelinks in the OICs 60 to the midplane interface card 58. In this manner,the exemplary embodiment of the HEU 14 is scalable to support up tothirty-six (36) RAUs 20 since the HEU 14 can support up to twelve (12)OICs 60. If less than thirty-four (34) RAUs 20 are to be supported bythe HEU 14, less than twelve OICs 60 can be included in the HEU 14 andconnected into the midplane interface card 58. An OIC 60 is needed forevery three (3) RAUs 20 supported by the HEU 14 in this embodiment. OICs60 can also be added to the HEU 14 and connected to the midplaneinterface card 58 if additional RAUs 20 are desired to be supportedbeyond an initial configuration. In this manner, the number of supportedRAUs 20 by the HEU 14 is scalable and can be increased or decreased, asneeded and in the field, by simply connecting more or less OICs 60 tothe midplane interface card 58.

FIG. 3 illustrates an exemplary distributed antenna system housingassembly 70 (referred to as “assembly 70”) that may be employed toprovide an HEU, such as the HEU 14 in FIG. 2. An HEU is simply at leastone communications component provided in an enclosure or housing. Aswill be described in more detail below, the assembly 70 is modular. Theassembly 70 is configured to be easily assembled in a factory or in thefield by a technician. Further, the assembly 70 supports a number offeatures that allow interface cards to be easily inserted and alignedwith respect to the midplane interface card 58 to ensure that properconnections are made with other components of the HEU 14 that form partof the distributed antenna system, such as the distributed antennasystem 12 in FIG. 1, for example. As illustrated in FIG. 3, the assembly70 includes an enclosure 72. The enclosure 72 is comprised of a bottomplate 74 (see also, FIG. 14B) and side plates 76A, 76B. An internalcavity 80 is formed in the space formed inside the bottom plate 74 andthe side plates 76A, 76B when assembled together for locating componentsof the HEU 14, such as the components illustrated in FIG. 2, forexample. A top plate 82 can also be provided and secured to the sideplates 76A, 76B, as illustrated in FIG. 6, to protect the internalcavity 80 and protect components of the HEU 14 disposed therein. Notethat only two plates can be provided for the enclosure 72, if desired.For example, one plate could be a first plate wherein a second plate isattached to the first plate. The first plate could be any of the bottomplate 74, the side plates 76A, 76B, and top plate 82. Also, the secondplate could be any of the bottom plate 74, the side plates 76A, 76B, andtop plate 82.

With continuing reference to FIG. 3, the enclosure 72 is configured tosupport the OICs 60 illustrated in FIG. 2. In this embodiment asillustrated FIG. 4, the OICs 60 are grouped together in pairs to form anoptical interface module (OIM) 84. Thus, an OIM 84 is comprised of two(2) OICs 60 that each support up to three (3) RAUs 20 and thus the OIM84 supports up to six (6) RAUs 20 in this embodiment. As illustrated inFIG. 4, each OIC 60 is provided as a PCB 86 with integrated circuitsprovided therein to provide electrical signal to optical signalconversions for communication downlinks and vice versa for communicationuplinks. An OIM plate 88 is provided to assist in coupling a pair ofOICs 60 together to form the OIM 84. As will be discussed in more detailbelow in this disclosure, the pair of OICs 60 are secured to the OIMplate 88 to form the OIM 84. The OIM plate 88 serves to support the OIC60 and contribute to the alignment the OICs 60 for proper insertion intoand attachment to the enclosure 72, which in turn assists in providingfor a proper and aligned connection of the OICs 60 to the midplaneinterface card 58, as shown in FIG. 3. In this embodiment, the PCBs 86are attached to shield plates 95A, 95B that are attached to the OIMplate 88 to provide mechanical, RF, and other electromagneticinterference shielding.

The OICs 60 are also secured together via standoff connectors 89 thatcontain alignment features to allow self-alignment between the OICs 60when connected to the midplane interface card 58, as illustrated in FIG.4 and as will be described in more detail in this disclosure. Connectoradapters 90 are disposed in the OIM plate 88 and provide for opticalconnections of OIC PCBs 86 of the OICs 60. The connector adapters 90 aredisposed through openings 92 in the OIM plate 88 to provide externalaccess when the OIM 84 is installed in the enclosure 72. RAUs 20 can beconnected to the connector adapters 90 to establish connections to theOICs 60 of the HEU 14, and thus provided as part of the distributedantenna system 12, via the optical fiber cables 36 in FIG. 1 beingconnected to the connector adapters 90. These connector adapters 90 mayreceive any type of fiber optic connector, including but not limited toFC, LC, SC, ST, MTP, and MPO. The OIM 84 is secured to the enclosure 72via spring-loaded connector screws 85 disposed in the OIM plate 88 thatare configured to be inserted into apertures 87 (see FIG. 5) to securethe OIM plate 88 to the enclosure 72, as illustrated in FIG. 3.

To provide flexibility in providing OIMs 84, the HEC 42, and thedownlink BIC 54 and uplink BIC 56 in the HEU 14, the enclosure 72provides for the midplane interface card 58 to be disposed inside theinternal cavity 80 extending between the side plates 76A, 76B in a datumplane 81, as illustrated in FIG. 3. As will be discussed in more detailbelow, alignment features are provided in the midplane interface card 58and the enclosure 72 such that proper alignment of the midplaneinterface card 58 with the enclosure 72 is effected when the midplaneinterface card 58 is inserted in the enclosure 72. Thus, when the OIMs84, the HEC 42, and the downlink BIC 54 and uplink BIC 56 are properlyand fully inserted into the enclosure 72, the alignment between thesecomponents and the enclosure 72 effect proper aligned connectionsbetween connectors on these components (e.g., connectors 94) and themidplane interface card 58. Proper connection to the midplane interfacecard 58 is essential to ensure proper connection to the propercomponents in the HEU 14 to support communications as part of adistributed antenna system supported by the HEU 14. Aligning theseconnections is important for proper connection, especially given thatthe enclosure 72 is modular and tolerances of the enclosure componentsin the enclosure 72 can vary.

To illustrate the alignment features to properly align the midplaneinterface card 58 with the enclosure 72, FIG. 5 is provided toillustrate a front view of the enclosure 72 with the midplane interfacecard 58 installed therein. FIG. 5 illustrates a front side 93 of themidplane interface card 58. FIG. 6 illustrates a rear perspective viewof the enclosure 72 with the midplane interface card 58 installed. NoHEU 14 components are yet installed in the enclosure 72 in FIG. 5. FIG.6 illustrates channels 91A that are disposed in the bottom plate 74 ofthe enclosure 72 to receive bottom portions of the HEC 42 and OIMs 84 toalign these components in the X and Y directions of the enclosure 72.Channels 91B (FIG. 14B) are also disposed on the top plate 82 and arealigned with the channels 91A disposed in the bottom plate 74 to receivetop portions of the HEC 42 and OIMs 84 to align these components in theX and Y directions. It is important that the midplane interface card 58be properly aligned with regard to the enclosure 72 in each of the X, Y,and Z directions, as illustrated in FIG. 5, because the midplaneinterface card 58 includes connectors 94A, 94B, 94C that receivecomplementary connectors (described in more detail below) fromcomponents of the HEU 14 installed in the enclosure 72.

The connectors 94A are disposed in the midplane interface card 58 anddesigned to accept connections from the HEC 42 and other like cards witha compatible complementary connector, as illustrated in FIG. 3. Theconnectors 94B are disposed in the midplane interface card 58 anddesigned accept digital connections from the OICs 60. The RF connectors94C are disposed in the midplane interface card 58 and designed toaccept RF connections from the OIC 60 (see element 195, FIGS. 21 and22). The enclosure 72 is designed such that alignment of the HEU 14components is effected with respect to the enclosure 72 when installedin the enclosure 72. Thus, if the connectors 94A, 94B, 94C are notproperly aligned with respect to the enclosure 72, components of the HEU14, by their alignment with the enclosure 72, may not be able toestablish proper connections with the midplane interface card 58 andthus will not be connected to the distributed antenna system provided bythe HEU 14.

In this regard, as illustrated in FIGS. 5 and 6, a midplane support 100is installed in the datum plane 81 of the enclosure 72 to align themidplane interface card 58 in the X, Y, and Z directions with regard tothe enclosure 72. The midplane support 100 may be a plate formed fromthe same material as the bottom plate 74, the side plates 76A, 76B,and/or the top plate 82. The midplane support 100 provides a surface tomount the midplane interface card 58 in the enclosure 72. A dividerplate 101 is also provided and attached to the midplane support 100, asillustrated in FIG. 6, to separate compartments for the downlink anduplink BICs 54, 56 and a power supply 59 (FIG. 6) to provide power forthe HEC 42 and other components of the HEU 14. As will also be describedin more detail below, the modular design of the enclosure 72 is providedsuch that the midplane support 100 is properly aligned in the datumplane 81 in the X, Y, and Z directions when installed in the enclosure72. Thus, if alignment features are disposed in the midplane support 100to allow the midplane interface card 58 to be properly aligned with themidplane support 100, the midplane interface card 58 can be properlyaligned with the enclosure 72, and as a result, the connectors of thecomponents of the HEU 14 installed in the enclosure 72 will be properlyaligned to the connectors 94A, 94B, 94C disposed in the midplaneinterface card 58.

As illustrated in FIG. 5, two alignment features 102 are disposed in themidplane support 100 and the midplane interface card 58 to align themidplane interface card 58 in the X, Y, and Z directions with respect tothe midplane support 100, and thus the enclosure 72. FIG. 7 illustratesa close-up view of the right-hand side of the midplane interface card 58installed on the midplane support 100 that also shows one of thealignment features 102. The alignment features 102 in this embodimentare comprised of PCB support guide pins 104 that are configured to bedisposed in alignment openings 106, 108 disposed in the midplaneinterface card 58 and midplane support 100, respectively. FIG. 8illustrates a front side 109 of the midplane interface card 58 withoutconnectors. The PCB support guide pins 104 are installed and configuredto be disposed through the alignment openings 106, 108. Before the PCBsupport guide pins 104 can be inserted through both alignment openings106, 108 disposed in the midplane interface card 58 and midplane support100, the alignment openings 106, 108 are aligned with the PCB supportguide pins 104. Thus, by this alignment, the midplane interface card 58is aligned in the X and Y directions with the midplate support 100. Forexample, the inner diameter of the openings 106, 108 may be 0.003 inchesor less larger that the outer diameter of the PCB support guide pin 104.Also, the tolerances between the center lines in the X direction of thealignment openings 106, 108 may be less than 0.01 inches or 0.005inches, as examples, to provide an alignment between the alignmentopenings 106, 108 before the PCB support guide pins 104 can be disposedthrough both alignment openings 106, 108. Any other tolerances desiredcan be provided.

Once the PCB support guide pins 104 are inserted into the openings 106,108, the midplane interface card 58 can be screwed in place to themidplane support 100. In this regard, additional openings 110 aredisposed in the midplane interface card 58, as illustrated in FIG. 5.These openings 110 are configured to align with openings 112 disposed inthe midplane support 100 when the alignment openings 106, 108 arealigned or substantially aligned. A total of twenty (20) or other numberof openings 110, 112 are disposed in the midplane interface card 58 andmidplane support 100, as illustrated in FIG. 5. Fasteners 114, such asscrews for example, can be disposed through the openings 110, 112 tosecure the midplane interface card 58 to the midplane support 100 andto, in turn, align the midplane interface card 58 to the midplanesupport 100 in the Z direction.

FIG. 8 illustrates the midplane interface card 58 without the fasteners114 disposed in the openings 110 to further illustrate the openings 110.The fasteners 114 are screwed into self-clinching standoff. For example,the self-clinching standoff may be disposed in the midplane support 100.The height tolerances of the self-clinching standoffs may be between+0.002 and −0.005 inches, as an example. The inner diameter of theopenings 110 may be 0.030 inches greater than the outer diameter of thefasteners 114, for example, since openings 110 are not used to providethe alignment provided by PCB support guide pins 104 and openings 106,108. Further, as illustrated in FIG. 5, openings 115 are disposed in themidplane support 100 to allow cabling to be extended on each side of themidplane interface card 58. The nominal distance in one embodimentbetween the midplane support 100 and the midplane interface card 58 wheninstalled is 0.121 inches, although any other distances could beprovided.

The midplane interface card 58 is also configured to receive directconnections from the downlink BIC 54 and the uplink BIC 56 wheninstalled in the enclosure 72. As illustrated in the rear view of theenclosure 72 in FIG. 9, the downlink BIC 54 and uplink BIC 56 aredesigned to be inserted through a rear side 116 of the enclosure 72.Referring back to FIG. 8, connector holes 116A, 116B are disposed on themidplane interface card 58 in FIG. 8 show where connectors are providedthat are connected to connectors 118 (see FIGS. 10A and 10B) of thedownlink BIC 54 and uplink BIC 56 when the downlink BIC 54 and uplinkBIC 56 are received are fully inserted into the enclosure 72. Thealignment features 102, by being provided between the midplane interfacecard 58 and the midplane support 100 as previously discussed, alsoprovide proper alignment of the connector holes 116A, 116B to beproperly aligned with the connectors 118 in the downlink BIC 54 anduplink BIC 56 when inserted in the enclosure 72.

FIGS. 10A and 10B illustrate a BIC assembly 120 that supports thedownlink BIC 54 or the uplink BIC 56 and is configured to be received inthe enclosure 72 to connect the downlink BIC 54 or the uplink BIC 56 tothe midplane interface card 58. The BIC assembly 120 is the same whethersupporting the downlink BIC 54 or the uplink BIC 56; thus, the BICsupported by the BIC assembly 120 in FIGS. 10A and 10B could be eitherthe downlink BIC 54 or the uplink BIC 56. The BIC assembly 120 includesa BIC support plate 122 that is configured to secure the downlink anduplink BICs 54, 56. Standoffs 124 are provided to support a BIC PCB 126of the downlink and uplink BICs 54, 56 above the BIC support plate 122.A BIC face plate 128 is coupled generally orthogonal to the BIC supportplate 122 to secure the downlink and uplink BICs 54, 56 to theenclosure, as illustrated in FIG. 9. Alignment features 130 are providedbetween the BIC support plate 122 and the BIC face plate 128 to ensurethat the BIC PCB 126, and thus its connector 118, are properly alignedin the X and Y directions, as illustrated in FIG. 9, when the downlinkand uplink BICs 54, 56 are inserted in the enclosure 72. Thus, theconnector 118 will be properly aligned with the enclosure 72 and thusthe connector holes 116A, 116B on the midplane interface card 58 toallow a proper connection between the downlink and uplink BICs 54, 56and the midplane interface card 58. The alignment features 130 willensure alignment of the BIC PCB 126 as long as the BIC PCB 126 isproperly installed on the BIC support plate 122, which will be describedin more detail below. As illustrated on the bottom side 127 of the BICassembly 120 in FIG. 11, the alignment features 130 in this embodimentare protrusions 132 attached to the BIC support plate 122 that areconfigured to be disposed through openings 134 disposed through the BICface plate 128, as illustrated in FIG. 10A. The downlink or uplink BICconnectors 50, 52 (see also, FIG. 2), as the case may be, are disposedthrough the BIC face plate 128 to allow BTS inputs and outputs to beconnected to the downlink and uplink BICs 54, 56, external to theenclosure 72 when the downlink and uplink BICs 54, 56 are fully insertedin the enclosure 72.

To provide alignment of the BIC PCB 126 to the BIC support plate 122,alignment features 140 are also disposed in the BIC PCB 126 and the BICsupport plate 122, as illustrated in FIGS. 10A, 10B, 11 and 12. Asillustrated therein, PCB support guide pins 142 are disposed throughalignment openings 144, 146 disposed in the BIC PCB 126 and BIC supportplate 122, respectively, when aligned. The alignment openings 144 and146 are designed to only be aligned to allow the PCB support guide pin142 to be disposed therein when the alignment openings 144, 146 are inalignment. For example, the tolerances between the alignment openings144, 146 may be less than 0.01 inches or less than 0.005 inches, asexamples, to ensure an alignment between the alignment openings 144, 146before the PCB support guide pins 142 can be disposed through bothalignment openings 144, 146. Any other tolerances desired can beprovided.

FIGS. 9-12 described above provide the BIC connectors 50, 52 disposedthrough the rear side 116 of the enclosure 70. To establish connectionswith the BIC connectors 50, 52, connections are established to the BICconnectors 50, 52 in the rear side 116 of the enclosure 72.Alternatively, the enclosure 72 could be designed to allow connectionsto be established to the downlink BIC 54 and the uplink BIC 76 from thefront side of the enclosure 72. In this regard, FIG. 13 is a sideperspective view of the assembly 70 of FIG. 3 with the downlink BICconnectors 50 for the downlink BIC and the uplink BIC connectors 52 forthe uplink BIC 56 disposed through a front side 147 of the enclosure 72.As illustrated therein, a downlink BIC connector plate 149 containingdownlink BIC connectors 50 disposed therein is disposed in the frontside 147 of the assembly 70. Similarly, an uplink BIC connector plate151 containing uplink BIC connectors 52 disposed therein is alsodisposed in the front side 147 of the assembly 70.

FIGS. 14 and 15 illustrate front and rear perspective views of anexemplary BIC connector plate, which can be BIC connector plate 149 or151. As illustrated therein, the BIC connectors 50 or 52 are disposedthrough the BIC connector plate 149 or 151 so that the BIC connectors 50or 52 can be accessed externally through the front side 147 of theassembly 70. Fasteners 153 can be disposed through openings 155 in theBIC connector plates 149 or 151 to fasten the BIC connector plates 149or 151 to the assembly 70. Channel guides 173 are attached to the BICconnector plates 149 or 151 that are configured to be received in thechannels 91A, 91B in the assembly 70 to assist in aligning the BICconnector plates 149 or 151 with the assembly 70 when disposing the BICconnector plates 149 or 151 in the assembly 70. Because the downlink BIC54 and uplink BIC 56 are disposed in the rear of the assembly 70, asillustrated in FIGS. 9-12, the BIC connectors 50 or 52 are provided inthe BIC connector plates 149 or 151 to connect the BIC connectors 50 or52 to the downlink BIC 54 or uplink BIC 56, as illustrated in FIG. 15and as will be described below with regard to FIGS. 16 and 17. Further,a BIC ribbon connector 157 is disposed in the BIC connector plates 149or 151 to connect to the downlink BIC 54 or uplink BIC 56 to carrystatus signals regarding the downlink BIC 54 or uplink BIC 56 to bedisplayed on visual indicators 161 disposed on the BIC connector plates149 or 151.

FIG. 16 is a rear side perspective view of the enclosure 72 illustratingcables 165, 167 connected to the BIC connectors 50, 52 being disposedthrough an opening 169 in the midplane support 100 and an opening 171 inthe divider plate 101. The cables 165, 167 provide connections betweenthe BIC connectors 50, 52 and the BIC ribbon connector 157 so that theBIC connectors 50, 52 can be disposed in the front side 147 of theassembly 70 with the downlink BIC 54 and the uplink BIC 56 disposed inthe rear of the assembly 70. FIG. 17 is a top view of the assembly 70further illustrating the routing of the cables 165, 167 connecting theBIC connectors 50, 52 and BIC ribbon connector 157 through the openings169, 171 to the downlink BIC 54 and uplink BIC 56.

The enclosure 72 is also provided as a modular design to allow theenclosure to be easily assembled and to effect proper alignment betweenthe various plates and components that form the enclosure 72. Forexample, FIG. 18 illustrates a front exploded perspective view of theenclosure 72. As illustrated therein, the enclosure 72 is formed fromthe side plates 76A, 76B being connected to and between the bottom plate74 and the top plate 82. The midplane support 100 is configured to bedisposed in the datum plane 81 (see FIG. 5) of the enclosure 72 whenassembled. The divider plate 101 is configured to be attached to themidplane support 100 generally orthogonal to the datum plane 81 todivide compartments for the downlink and uplink BICs 54, 56 and a powermodule disposed in the HEU 14 on the rear side of the midplane support100.

To further illustrate the modularity and ease in assembly of theenclosure 72, FIGS. 19A and 19B illustrate top and bottom perspectiveview, respectively, of the enclosure 72 to further illustrate how theside plates 76A, 76B are attached to the top plate 82 and bottom plate74. In this regard, the top and bottom plates 82, 74 include analignment feature in the form of locating tabs 150, 152. The locatingtabs 150, 152 are integrally formed in the top and bottom plates 74, 82and are configured to engage with complementary alignment openings oralignment slots 154, 156 integrally disposed in the side plates 76A,76B. FIGS. 19A and 19B also illustrates a close-up view of the top plate82 attached to the side plate 76B and the locating tabs 150 engaged withthe alignment slots 154. This allows the top and bottom plates 74, 82 tobe attached in proper alignment quickly and easily with the side plates76A, 76B when assembling the enclosure 72. In the enclosure 72, thereare four (4) locating tabs 150, 152 on each side of the top and bottomplates 82, 74, and four (4) complementary alignment slots 154, 156disposed on each side of the side plates 76A, 76B, although any numberof locating tabs and slots desired can be employed. Fasteners can thenbe employed, if desired to secure the locating tabs 150, 152 within thealignment slots 154, 156 to prevent the enclosure 72 from disassembling,as illustrated in FIG. 20. FIG. 20 also illustrates a close-up view ofthe top plate 82 attached to the side plate 76B in this regard.

As illustrated in FIG. 20, the top plate 82 contains rolled or bent upsides 180 that are configured to abut tightly against and a top insideside 182 of the side plate 76B. The same design is provided between thetop plate 82 and the side plate 76A, and the bottom plate 74 and theside plates 76A, 76B. An outer width W₁ of the top and bottom plates 82,74 is designed such that the fit inside an inner width W₂ of the sideplates 76A, 76B, as illustrated in FIG. 19A. Fasteners 184 disposed inopenings 186 in the side plates 76A, 76B and openings 188 in the top andbottom plates 82, 74 pull the side plates 76A, 76B and the top andbottom plates 82, 74 close together tightly to provide a tight sealtherebetween. Further, as illustrated in FIG. 20, an alignment tab 181extending from the midplane support 100 is shown and extends into a slot183 disposed in the top plate 82 to further align the midplane support100 with the enclosure 72.

FIG. 21 also illustrates alignment features provided in the midplanesupport 100 that are configured to align the midplane support 100 withthe enclosure 72. As illustrated in FIG. 21, the top plate 82 includesintegral alignment slots 160 in the datum plane 81 when the top plate 82is secured to the side plate 76B. The side plate 76B also includesalignment slots 162 integrally disposed along the datum plane 81 whenthe side plate 76B is secured to the top plate 82. The midplane support100 includes locating tabs 164 that are disposed through the alignmentslots 160, 162 when the midplane support 100 is properly aligned withthe enclosure 72 and the top plate 82 and side plate 76B (see also, FIG.7). In this manner, as previously described, when the midplane interfacecard 58 is properly aligned with the installed midplane support 100, themidplane interface card 58 is properly aligned with the enclosure 72 andthus any HEU 14 components installed in the enclosure 72. Alignmentslots 166 similar to alignment slots 160 are also integrally disposed inthe bottom plate 74, as illustrated in FIG. 19B. These alignment slots166 are also configured to receive locating tabs 168 in the midplanesupport 100, as illustrated in FIG. 19B, to align the midplane support100.

Further, as illustrated in FIGS. 19A and 19B, the enclosure 72 is alsoconfigured to receive and support removable mounting brackets 170A, 170Bto secure the enclosure 72 to an equipment rack. As illustrated therein,the mounting brackets 170A, 170B include folded down components thatform tabs 172A, 172B. The side plate 76A, 76B include integral alignmentslots 174, 176, respectively, that are configured to receive the tabs172A, 172B. To secure the tabs 172A, 172B to the enclosure 72, fasteners178A, 178B are disposed through openings 179A, 179B in the tabs 172A,172B, respectively, and secure to the top plate 82 and bottom plate 74.

Other features are provided to support alignment of components of theHEU 14 and to support proper connection of these components to themidplane interface card 58. For example, one of these components is theOIM 84, as previously discussed. The OIM 84 is illustrated in FIG. 22,wherein fiber routing guides 190 can be disposed on the outside of thePCB 86 of the OIC 60 to assist in routing optical fibers 192 fromconnector adapters 90 that are configured to connect to optical fibersconnected to the RAUs 20 (see FIG. 2). The optical fibers 192 areconnected to the electronic components of the OIC 60 to convert thereceived optical signals from the RAUs 20 into electrical signals to becommunicated to the uplink BIC 56 via connector 194 and RF connectors195 that are connected to the midplane interface card 58 when the OIM 84is inserted into the enclosure 72, as previously discussed.

As previously discussed, the OIM 84 includes two OICs 60 connected tothe OIM plate 88 to be disposed in channels 91A, 91B in the enclosure72. Also, by providing two OICs 60 per OIM 84, it is important that theconnectors 194 are properly aligned and spaced to be compatible with thealignment and spacing of the complementary connectors 94B in themidplane interface card 58 (see FIG. 5). Otherwise, the OICs 60 may notbe able to be properly connected to the midplane interface card 58. Forexample, if the PCBs 86 of the OICs 60 are not both secured in properalignment to the OIM plate 88, as illustrated in FIG. 23, one or bothOICs 60 may not be aligned properly in the Z direction.

In this regard, FIG. 24 illustrates an alignment feature 200 to ensurethat the PCBs 86 of the OICs 60 are properly secured and aligned withregard to the OIM plate 88 in the Z direction. As illustrated in FIG. 24and more particularly in FIG. 25, an alignment block 202 is provided. Asillustrated in FIG. 25, the alignment block 202 includes two alignmentsurfaces 204A, 204B. As illustrated in FIGS. 24 and 25, alignmentsurface 204A is configured to be disposed against the surface of the PCB86. Alignment surface 204B is configured to be disposed against a rearsurface 206 of the OIM plate 88, as also illustrated in FIG. 24. Asillustrated in FIG. 25, guide pin 208 extends from the alignment surface204A that is configured to be disposed in an opening in the PCB 86 ofthe OICs 60. An opening 210 disposed in the alignment surface 204A isconfigured to align with an opening disposed in the PCB 86 wherein afastener can be disposed therein and engaged with the opening 210 tosecure the PCB 86 to the alignment block 202. To align the alignmentblock 202 to the PCB 86, the guide pin 208 is aligned with an opening inthe PCB 86 and inserted therein when aligned.

The alignment surface 204B also contains an opening 212 that isconfigured to receive a fastener 214 (FIG. 23) disposed through the OIMplate 88 and engage with the opening 212. Some of the fasteners 214 maybe configured to also be disposed through openings in the connectoradapters 90, as illustrated in FIG. 23, to secure both the connectoradapters 90 to the OIM plate 88 and the OIM plate 88 to the OICs 60. Inthis manner, the OIM plate 88 is secured to the alignment block 202, andthe alignment block 202 is aligned and secured to the PCB 86. Thus, theOIM plate 88 is aligned with the PCB 86 of the OIC 60 in the Zdirection.

Further, when tolerances are tight, it may be difficult to ensure propermating of all connectors 194, 94B between the OICs 60 and the midplaneinterface card 58. For example, as illustrated in FIG. 23, if thespacing between standoffs 196 securing and spacing apart the PCBs 86 ofthe OICs 60 is not the same as the spacing between connectors 94B in themidplane interface card 58, alignment of the OICs 60 in the X, Y, or Zdirections may not be proper, and thus only one or neither OIC 60 may beable to be connected to the midplane interface card 58 and/or withoutdamaging the midplane interface card 58 and/or its connectors 94B.

In this regard, FIG. 26A illustrates a rear perspective view of the OIM84 of FIGS. 23 and 24 with standoffs 196 provided between the two PCBs86 of the OICs 60 that allow one PCB 86 to float with regard to theother PCB 86. FIG. 26B illustrates a rear perspective view of the OIM 84of FIG. 26A within optional shield plates 95A, 95B installed to the PCBs86 and to the OIM plate 88 to provide mechanical, RF, and otherelectromagnetic interference shielding. In this regard, tolerances areeased when the OICs 60 are secured to the OIM plate 88 to allow oneconnector 194 of an OIC 60 to move or float slightly in the X, Y, or Zdirections with regard to the other OIC 60, as illustrated in FIGS. 26Aand 26B. FIG. 27 illustrates a close-up view of one standoff 196 betweentwo PCBs 86A, 86B of the OICs 60. As will be described in more detailbelow, the standoff 196 is allowed to float about the top PCB 86A toallow the positioning or orientation of the top PCB 86A to move slightlyin the X, Y, or Z directions with regard to the bottom PCB 86B.

FIG. 28 is a side cross-sectional view of the top and bottom PCBs 86A,86B of the OIM 84 mounted to each other with the standoff 196, asillustrated in FIGS. 26A and 26B and 28, to further illustrate thefloating top PCB 86A. In this regard, the standoff 196 is comprised of abody 199. The body 199 of the standoff 196 is also illustrated in theperspective, side and top view of the standoff in FIGS. 29A-29C,respectively. The body 199 includes a first collar 220 at a first end222 of the body 199 of an outer diameter OD₁ than is smaller than anouter diameter OD₂ of a second collar 224 located at a second end 226 ofthe body 199, as illustrated in FIG. 28-30. The first and second collars220, 224 are configured to be received within openings 228, 230 of thetop and bottom PCBs 86A, 86B, as illustrated in FIG. 28. The first end222 and second end 226 of the body 199 contains shoulders 232, 234 thatlimit the amount of disposition of the first and second collars 220, 224through the openings 228, 230 in the top and bottom PCBs 86A, 86B.

As illustrated in FIG. 28, the second collar 224 is designed so that theouter diameter OD₂ includes a tight tolerance with the inner diameter ofthe opening 230. In this manner, the second collar 224 will not floatwithin the opening 230. Further, a height H₂ of the second collar 224(see FIG. 29C) is less than a width W₃ of the PCB 86A and opening 230disposed therein, as illustrated in FIG. 28. This allows a head 236 of afastener 238 to be secured directly onto the outer surface 239 of thebottom PCB 86B when disposed through a threaded shaft 240 of the body199 to firmly secure the standoff 196 to the bottom PCB 86B. Because ofthe outer diameter OD₂ and height H₂ provided for the second collar 224of the standoff 196, the bottom PCB 86B does not float.

However, to allow the top PCB 86A to float, the outer diameter OD₁ andheight H₁ of the first collar 220 is different from that of the secondcollar 224. In this regard, as illustrated in FIGS. 28-29C and 30, theouter diameter OD₁ of the first collar 220 is smaller than the innerdiameter of the opening 228. A gap G is formed therebetween to allow thefirst collar 220 to move slightly with respect to the opening 228 whendisposed therein. Further, the height H₁ of the first collar 220 istaller than the width W₁ of the top PCB 86A, as illustrated in FIG. 28.Thus when a fastener 242 is disposed within the threaded shaft 240 andtightened, a head 244 of the fastener 242 will rest against a topsurface 246 of the first collar 220. Because the first collar 220extends in a plane about a top surface 248 of the top PCB 86A, the head244 of the fastener 242 does not contact the top surface 248 of the PCB86A. Thus, when the fastener 242 is tightened, a friction fit is notprovided between the head 244 and the top surface 248 of the PCB 86A,allowing the top PCB 86A to float with respect to the standoff 196 andthe bottom PCB 86B.

FIG. 31 illustrates an alternative standoff 196′ that is the same as thestandoff 196, but the thread shaft does not extend all the way throughthe body 199′ like the standoff 196 in FIG. 30. Instead, the threadshafts 240A′, 240B′ are separated. The standoff 196′ can still beemployed to provide the floating PCB 86 features discussed above. Alsonote that the standoffs 196, 196′ configured to allow a PCB to float canalso be provided for the standoffs 196, 196′ provided to install anyother components of the HEU 14, including but not limited to thedownlink BIC 54 and the uplink BIC 56. Further, the design of the bodies199, 199′ may include a hexagonal outer surface over the entire lengthof the bodies 199, 199′.

FIGS. 32A and 32B are side cross-sectional views of an alternativestandoff 250 that can be employed to secure the OIC PCBs 86 and provideone of the OIC PCBs 86 as a floating PCB. The alternative standoff 250may be employed to secure the OIC PCBs 86 when the shield plates 95A,95B are installed, as illustrated in FIG. 26B. In this regard, onestandoff 252 is configured to be disposed within another standoff 254.The first standoff 252 contains a thread shaft 256 that is configured toreceive a fastener to secure a shield plate 95 to the standoff 252 andthe OIM 84. The standoff 252 contains a threaded member 255 that isconfigured to be secured to a threaded shaft 257 disposed in thestandoff 254. The standoff 254 contains a collar 258 similar to thecollar 220, as described above in FIGS. 28-29B, that surrounds thethreaded shaft 257 and is configured to be received inside an opening ofan OIC PCB 86 having a greater inner diameter than the outer diameterOD₃ of the collar 258. This allows an OIC PCB 86 disposed on the collar258 to float with respect to another OIC PCB 86 secured to a threadshaft 260 of the standoff 254. The standoff 254 has a collar 262 havingan outer diameter OD₄ that is configured to be received in an opening inan OIC PCB 86 that does not allow float.

Another alignment feature provided by the embodiments disclosed hereinis alignment assistance provided by the digital connectors disposed inthe midplane interface card 58 that accept digital connections from theOICs 60, the downlink BIC 54, and the uplink BIC 56. As previouslydiscussed and illustrated, digital connectors, including connectors 94B,disposed in the midplane interface card 58 receive complementary digitalconnectors 194 from the OICs 60, the downlink BIC 54, and the uplink BIC56 when inserted into the enclosure 72. The OICs 60, the downlink BIC54, and the uplink BIC 56 are designed such that their digitalconnections are first made to corresponding digital connectors disposedin the midplane interface card 58 when inserted into the enclosure 72before their RF connections are made to RF connectors disposed on themidplane interface card 58. In this manner, these digital connectionsassist in aligning the OICs 60, the downlink BIC 54, and the uplink BIC56 in the X and Y directions with regard to the midplane interface card58.

In this regard, FIG. 33 illustrates a side view of the assembly 70showing a digital connector 194 from an OIC 60 being connected to acomplementary connector 94B disposed in the midplane interface card 58.As illustrated therein, the digital connector 194 disposed in the OIC 60is designed such that the digital connector 194 makes a connection withthe complementary connector 94B in the midplane interface card 58 beforean RF connector 195 disposed in the OIC 60 makes a connection with thecomplementary RF connector 94C disposed in the midplane interface card58. In this regard, when the digital connector 194 begins to connectwith the complementary connector 94B, the digital connector 194 alignswith the complementary connector 94B. The end of the RF connector 195 inthe OIC 60 is still a distance D away from the complementary RFconnector 94C. In one non-limiting embodiment, the distance D may be0.084 inches. Because the digital connectors 194 on the OICs 60 are in afixed relationship to the RF connectors 195 provided therein in thisembodiment, alignment of the digital connectors 194 also providesalignment of the RF connectors 195 of the OICs 60 to the complementaryRF connectors 94C disposed in the midplane interface card 58 as well.Thus, as the digital connector 194 is fully inserted in thecomplementary connector 94B, the RF connector 195 will be aligned withthe complementary RF connector 94C when disposed therein. Alignment ofthe RF connector 195 may be important to ensure efficient transfer of RFsignals. This feature may also be beneficial if the RF connectionsrequire greater precision in alignment than the digital connections. Thesame alignment feature can be provided for the downlink BIC 54 anduplink BIC 56.

As previously discussed and illustrated in FIG. 4, the OIM plate 88provides support for the connectors 90 and for attaching the OICs 60 tothe OIM plate 88 to provide alignment of the OICs 60 when inserted intothe enclosure 72. An OIM plate 88 is provided to assist in coupling apair of OICs 60 together to form the OIM 84. The OIM plate 88 serves tosupport the OICs 60 and contributes to the alignment the OICs 60 forproper insertion into and attachment to the enclosure 72, which in turnassists in providing a proper and aligned connection of the OICs 60 tothe midplane interface card 58. In this regard, as illustrated in FIG.34, one feature that can be provided in the OIM 84 to allow the OIMplate 88 to be provided in embodiments disclosed herein is to provide anOIC PCB 86 that extends beyond receiver optical sub-assemblies (ROSAs)and transmitter optical sub-assemblies (TOSAs) provided in the OIC 60.

As illustrated in FIG. 34, a top perspective view of the OIM 84 isprovided illustrating the extension of OIC PCBs 86 beyond transmitteroptical sub-assemblies (TOSAs) 262 and receiver optical sub-assemblies(ROSAs) 260. The TOSAs 262 and ROSAs 260 are connected via opticalfibers 263, 265 to the connectors 90 that extend through the OIM plate88 to allow connections to be made thereto. By extending the OIC PCBsbeyond the TOSAs 262 and ROSAs 260, the OIM plate 88 can be secured tothe OIC PCBs 86 without interfering with the TOSAs 262 and ROSAs 260. Inthis embodiment, the TOSAs 262 and ROSAs 260 are mounted or positionedon an end of a PCB to transmit and/or receive optical signals interfacedwith electrical signal components disposed in the OIC PCB 86. Mountingor positioning of TOSAs 262 and ROSAs 260 on the end of a PCB may limitthe length of exposed, unshielded wire extensions between the TOSAs 262and ROSAs 260 and printed traces on the PCB. This provides for signalintegrity of the signals after conversion to electrical signals.

Thus, a sufficient space is provided to allow for the TOSAs 262 andROSAs 260 to extend beyond an end of a PCB. In this regard, openings264, 266 are disposed in the OIC PCB 86 in this embodiment. The openings264, 266 allow the TOSAs 262 and ROSAs 260 to be disposed in the OIC PCB86 without the TOSAs 262 and ROSAs 260 extending beyond an end 268 ofthe OIC PCB 86 where the OIM plate 84 is disposed. Thus, the openings264, 266 allow the TOSAs 262 and ROSAs 260 to be disposed at an end 270of the PCB where the openings 264, 266 start, but not at the end 268 ofthe OIC PCB 86 where the OIM plate 88 is located. In this manner, spaceis provided for the TOSAs 262 and ROSAs 260 such that they do notinterfere with or prevent the OIM plate 88 from being disposed at theend 268 of the OIC PCB 86.

It may also be desired to provide a cooling system for the assembly 70.The components installed in the assembly 70, including the downlink BIC54, the uplink BIC 56, the HEC 42, and the OICs 60 generate heat.Performance of these components may be affected if the temperature dueto the generated heat from the components is not kept below a thresholdtemperature. In this regard, FIGS. 35 and 36 illustrate the assembly 70and enclosure 72 of FIG. 3 with an optional cooling fan 280 installedtherein to provide cooling of components installed in the enclosure 72.View of the cooling fan 280 is obscured by a cooling fan protector plate282 in front perspective view of the assembly 70 in FIG. 35; however,FIG. 36 illustrates a side cross-sectional view of the assembly 70 andenclosure 72 showing the cooling fan 280 installed in the enclosure 72behind the cooling fan protector plate 282 attached to the enclosure 72.In this embodiment, cooling is provided by the cooling fan 280 takingair into the enclosure 72 through openings 284 disposed in the coolingfan protector plate 282 and drawing the air across the components in theenclosure 72, as will be described in more detail below. The air may bepushed through the rear of the enclosure 72 through an air outlet, asillustrated in FIG. 36. For example, the cooling fan 280 may be rated todirect air at a flow rate of sixty (60) cubic feet per minute (CFM) orany other rating desired.

With continuing reference to FIG. 36, a lower plenum 286 and an upperplenum 288 is provided in the enclosure 72. The lower plenum 286 isprovided to direct air pulled in the enclosure 72 by the cooling fan 280initially to the bottom of the enclosure 72 to allow the air to then bedirected upward through OICs 60 installed in the enclosure 72 and to theupper plenum 288 to be directed to the rear and outside of the enclosure72. Passing air across the OICs 60 cools the OICs 60. This air flowdesign is further illustrated in the air flow diagram of FIG. 37. Inthis regard, with reference to FIG. 36, a fan duct 290 is providedbehind the cooling fan 280 to direct air drawn into the enclosure 72 bythe cooling fan 280. A plate 292 is installed in the fan duct 290 todirect air flow down from the fan duct 290 into the lower plenum 286.The air from the lower plenum 286 passes through openings disposed in alower plenum plate 294 and then passes through the openings disposedbetween OICs 60 wherein the air then passes through openings 296disposed in an upper plenum plate 298, as illustrated in FIG. 38. Inthis manner, air is directed across the OICs 60 to provide cooling ofthe OICs 60. Air then entering into the upper plenum 288 is free to exitfrom the enclosure 72, as illustrated in FIG. 36. The upper plenum 288is open to the outside of the enclosure 72 through the rear of theenclosure 72, as illustrated in FIGS. 36 and 37 and in FIG. 39.

Further, as illustrated in FIGS. 40 and 41, openings 300 and 302 canalso be disposed in the upper plenum plate 298 above the uplink BIC 56and in the downlink BIC 54 to provide further movement of air forcooling purposes. These openings 300, 302 allow some of the air flowinginto the enclosure 72 from the cooling fan 280 to be drawn from thelower plenum 286 into the downlink BIC 54 and then into the uplink BIC56 via openings 302. Air can then be directed from the uplink BIC 56through openings 300 and into the upper plenum 288 outside of theenclosure 72.

Further, as illustrated in FIGS. 36, 39, and 41 an optional secondcooling fan 301 is provided below the upper plenum plate 298. In thismanner, some of the air from the enclosure 72 is drawn through the powersupply 59 by the second cooling fan 301 to provide cooling of the powersupply 59. For example, the second cooling fan 301 may be rated todirect air at a flow rate of thirteen (13) cubic feet per minute (CFM)or any other rating desired.

Many modifications and other embodiments set forth herein will come tomind to one skilled in the art to which the embodiments pertain havingthe benefit of the teachings presented in the foregoing descriptions andthe associated drawings. Therefore, it is to be understood that thedescription and claims are not to be limited to the specific embodimentsdisclosed and that modifications and other embodiments are intended tobe included within the scope of the appended claims. For example, theembodiments disclosed herein can be employed for any type of distributedantenna system, whether such includes optical fiber or not.

It is intended that the embodiments cover the modifications andvariations of the embodiments provided they come within the scope of theappended claims and their equivalents. Although specific terms areemployed herein, they are used in a generic and descriptive sense onlyand not for purposes of limitation

What is claimed is:
 1. An optical interface card, comprising: a printedcircuit board (PCB) having a first perimeter including a first end and asecond end opposite the first end; at least one opening disposed in thePCB between the first end and the second end of the PCB and having asecond perimeter including at least one first opening end and at leastone second opening end opposite the at least one first opening end,wherein the second perimeter does not extend to the first perimeter; andat least one optical sub-assembly (OSA) mounted to the at least onefirst opening end and extending into the at least one opening.
 2. Theoptical interface card of claim 1, wherein the at least one opening doesnot extend to the first end of the PCB.
 3. The optical interface card ofclaim 2, wherein the at least one OSA does not extend to the first endof the PCB.
 4. The optical interface card of claim 1, wherein the atleast one OSA is comprised of at least one of a transmitter OSA (TOSA)and a receiver OSA (ROSA).
 5. The optical interface card of claim 1,further comprising at least one electrical conductor extending in asubstantially straight line from an end of the at least one OSA andelectrically connected with one or more printed traces on the PCB. 6.The optical interface card of claim 1, wherein the at least one openingis comprised of at least one rectangular opening.
 7. The opticalinterface card of claim 1, further comprising at least one optical fiberrouting guide configured to route one or more optical fibers connectedto the at least one OSA.
 8. The optical interface card of claim 1,further comprising a mounting plate mounted to the first end of the PCBin a plane orthogonal to a plane of the PCB.
 9. The optical interfacecard of claim 8, further comprising at least one alignment block mountedin at least one opening disposed in the PCB proximate the first end ofthe PCB and at least one opening disposed in the mounting plate to alignthe PCB to the mounting plate.
 10. The optical interface card of claim9, further comprising at least one guide pin disposed in the at leastone alignment block engaged with the at least one opening disposed inthe PCB.
 11. An optical interface assembly, comprising: a first opticalinterface card (OIC) having a first perimeter including a first end anda second end, comprising: at least one first opening between a first endand a second end of the first OIC having a second perimeter including atleast one first opening end, wherein the second perimeter does notextend to the first perimeter; and at least one first opticalsub-assembly (OSA) mounted to the at least one first opening end andextending into the at least one first opening; and a second OIC,comprising: at least one second opening between a first end and a secondend of the second OIC having at least one second opening end; and atleast one second OSA mounted to the at least one second opening end andextending into the at least one second opening; and at least onestandoff disposed between the first OIC and second OIC.
 12. The opticalinterface assembly of claim 11, wherein the at least one first openingdoes not extend to the first end of the first OIC, and wherein the atleast one second opening does not extend to the second end of the secondOIC.
 13. The optical interface assembly of claim 12, wherein the atleast one first OSA does not extend to the first end of the first OIC,and wherein the at least one second OSA does not extend to the first endof the second OIC.
 14. The optical interface assembly of claim 11,wherein the at least one first OSA and the at least one second OSA areeach comprised of at least one of a transmitter OSA (TOSA) and areceiver OSA (ROSA).
 15. The optical interface assembly of claim 11,further comprising at least one electrical conductor extending in asubstantially straight line from an end of the at least one OSA andelectrically connected with one or more printed traces on the PCB. 16.The optical interface assembly of claim 11, further comprising amounting plate mounted to the first end of the first OIC and the firstend of the second OIC in a plane orthogonal to a plane of the first OICand a plane of the second OIC.
 17. A method of assembling an opticalinterface card, comprising: providing a printed circuit board (PCB)having a first perimeter including a first end and a second end oppositethe first end, and at least one opening having a second perimeterincluding at least one first opening end, wherein the second perimeterdoes not extend to the first perimeter; and mounting at least oneoptical sub-assembly (OSA) to the at least one first opening end of theat least one opening disposed in the PCB between the first end and thesecond end of the PCB.
 18. The method of claim 17, further comprisingplacing the at least one opening in the PCB prior to the step ofmounting.
 19. The method of claim 18, further comprising not extendingthe at least one opening to the first end of the PCB.
 20. The method ofclaim 17, further comprising not mounting the at least one OSA to extendto the first end of the PCB.
 21. The method of claim 17, wherein the atleast one OSA is comprised of at least one of a transmitter OSA (TOSA)and a receiver OSA (ROSA).
 22. The method of claim 17, furthercomprising routing at least one optical fiber from the at least one OSAthrough at least one routing guide mounted to the PCB.
 23. The method ofclaim 17, mounting the first end of the PCB to a mounting plate disposedin a plane orthogonal to a plane of the PCB.
 24. An optical interfacecard, comprising: a printed circuit board (PCB) having a first end and asecond end opposite the first end; at least one opening disposed in thePCB between the first end and the second end of the PCB and having atleast one first opening end and at least one second opening end oppositethe at least one first opening end; at least one optical sub-assembly(OSA) mounted to the at least one first opening end and extending intothe at least one opening; and at least one alignment block mounted in atleast one opening disposed in the PCB proximate the first end of the PCBand at least one opening disposed in the mounting plate to align the PCBto the mounting plate.
 25. The optical interface card of claim 24,further comprising at least one guide pin disposed in the at least onealignment block engaged with the at least one opening disposed in thePCB.